OK, an understated low-five might follow after either makes a good play. But usually it's just a smile, maybe a slight nod. Quiet and introspective by nature, Cunningham and Pericak (pronounced "pre-check") leave the animated celebrations to others.

"We might do something subtle, or glance over to the other guy and say, 'Good job,' " Cunningham said. "We're definitely there for each other."

And there for CU, which ranks second among Big 12 teams in rushing defense and No. 7 nationally, thanks in large part to Cunningham, a 6-foot-1, 280-pound junior, and Pericak, a 6-foot-4, 280-pound sophomore. Another big effort will be needed Saturday against Georgia's pro-style offense that relies heavily on the running game.

"Curtis and Will clog that middle," CU junior safety Anthony Perkins said. "They do a great job of just eating up blockers. When they eat up blockers, that allows the linebackers and safeties to make all the tackles, make the plays. There's no way our defense would be where it is today if it weren't for those guys."

Personality-wise, Cunningham and Pericak could pass for brothers. They are, in a way. Both are sons of the Front Range. Both played ball in the Denver area — Cunningham at Columbine, Pericak at Boulder High — so there's a bond.

"You've always got that Colorado pride, being a homegrown boy," Pericak said with a grin.

And neither considered leaving home. Cunningham did not take any other official recruiting visits. Pericak made a courtesy recruiting trip to Colorado State, but there was little doubt where he was headed. His mother, Wynn, works in the Denver office of University of Colorado president Bruce Benson, and he has a brother and sister who recently earned CU diplomas.

Is it any wonder they've developed a chemistry?

"Curtis and I play off each other," Pericak said. "If we slide one direction, the other person's job is to switch responsibilities. If we see something, we might make eye contact and run something."

Defensive line coach Romeo Bandison likes what he has in the middle.

"They work hard. They do everything that I ask," he said. "They're very reliable. They still have a ways to go. But they're on their way."

The same goes for their classwork. Cunningham is an international affairs major on track to graduate in four years. Pericak is following his siblings as a finance major and may graduate in three years. That's right, three years. If that happens, Pericak would play his final two seasons while enrolled in graduate school.

For now, they plan on sticking together, as each is in his second year as a starter.

"We've played together now for quite a while," Cunningham said, "so we're playing fast because we're confident in what we're doing and what the other guy is doing. And we'll need to play fast against Georgia, that's for sure."